18 C.F.R. § 1301.5
(b) Multitrack processing. TVA has established three tracks for handling requests and the track to which a request is assigned will depend on the nature of the request and the estimated processing time. Among the factors TVA may consider are the number of records requested, the number of pages involved in processing the request and the need for consultations or referrals. TVA will also designate a specific track for requests that are granted expedited processing, in accordance with the standards set forth in paragraph (e) of this section. TVA will advise requesters of the track into which their request falls and, when appropriate, will offer the requesters an opportunity to narrow or modify their request so that it can be placed in a different processing track.
(c) Unusual circumstances. Whenever the statutory time limit for processing a request cannot be met because of “unusual circumstances,” and TVA extends the time limit on that basis, TVA will, before expiration of the 20-day period to respond, notify the requester in writing of the unusual circumstances involved and of the date by which TVA estimates processing of the request will be completed. Where the extension exceeds 10 working days, TVA will, as described by the FOIA, provide the requester with an opportunity to modify the request or arrange an alternative time period for processing the original or modified request. TVA will make available its FOIA Officer or its FOIA Public Liaison for this purpose. A list of agency FOIA Public Liaisons is available at https://www.foia.gov/report-makerequest.html. TVA will also alert requesters to the availability of the Office of Government Information Services (OGIS) to provide dispute resolution services. As used in this paragraph, “unusual circumstances” means, but only to the extent reasonable necessary to the proper processing of the particular requests:
(e) Expedited processing.
(1) TVA will process requests and appeals on an expedited basis whenever it is determined that they involve: